1. Field of the Invention
This invention relates to memory storage circuits and, more particularly, to non-volatile latches.
2. Description of the Related Art
The following descriptions and examples are given as background information only.
A latch may generally refer to any microelectronic device that can store information. In many cases, a latch may be configured to produce complementary outputs that are stable in one of two logic states. The complementary outputs are oftentimes referred to as differential outputs, in that while one output is at one logic state, the other output is at the second logic state. The outputs can be referenced as a “true,” “on,” “high,” or “1” logic level and as a “false,” “off,” “low,” or “0” logic level. In some cases, latches are configured as volatile circuits in that they lose data in the absence of power. In other cases, however, latches may be configured as nonvolatile circuits in that they can retain stored data in the absence of power. In some cases, volatile circuits may provide a more rapid response than conventional nonvolatile circuits and, therefore, may provide faster read times.
Volatile latches, however, often require relatively high voltages for operation, such as on the order of more than approximately 15 volts. Some conventional nonvolatile latches may necessitate slightly lower voltages for operation, such as between approximately 8 volts and approximately 12 volts. Such a range of voltage levels may still be undesirably high in some cases, particularly as the drive to produce microelectronic devices that can process larger amounts of information continues and microelectronic devices are scaled down to smaller sizes making high voltage programming more difficult. In addition, conventional nonvolatile latches may require relatively long programming times, such as 10 ms, for example. Such relatively long programming times may undesirably limit the progress of producing devices which can process information quickly, which is commonly a high priority objective in the design of microelectronic devices.
It would, therefore, be advantageous to develop a latch which can be programmed in a relatively small amount of time and/or operate at a relatively low voltage, particularly in comparison to conventional latches. It would be further beneficial for such a latch to be nonvolatile such that data may be stored therein when power is terminated from the circuit. Furthermore, it would be advantageous to create a nonvolatile latch with relatively fast program and read times, particularly in reference to conventional volatile latches.